Congratulations on fixing the problem, looks like it was a real pain.
Just a couple quick notes on some of the things I read in the thread here...
Regarding your CSS structure, I've always found best results to start off my Font-Family tags with a web-safe font like the standard Arial, Tahoma, Verdana, etc etc. "Arial Narrow" will only be displayed properly on a small amount of computers that have this font installed, therefore to keep a consistant look I always start with fonts I know for certain will be on 90%+ of computers that view the site. Of course, as I said that's just my habit and not necissarily a dictum as to how you should code your sites.
Also, watch for leaving any tags open in any CSS, be it a linked sheet or inline STYLE attribute, I had a helluva time with a site once that turned out to be I left a margin: open without any definition or closing ; .
Finally, when working with skinning SOLPART, I've found it easiest to leave the [MENU] tag as "naked" as possible, with as few surrounding tags as possible, then there are less possibilities of other deprecations or cascades from other defined elements.
Just my $0.02...
SB